1. Field of the Invention
The present invention relates to a semiconductor device having a pad, and more particularly to a semiconductor device having a pad with which a terminal is brought into contact upon inspection or measurement of electric properties of a semiconductor element.
2. Description of the Background Art
A probe card having a plurality of probe styluses disposed thereon has been employed for inspection of electric properties of a semiconductor element in a wafer state. The probe card is disclosed, e.g., in Japanese Patent Laying-Open No. 1-128535.
Upon the inspection of electric properties, a probe stylus of the probe card is pressed against the pad to achieve electrical conduction between the semiconductor element and a tester. The probe stylus is configured to touch the pad surface at a prescribed angle other than a right angle. Thus, after establishment of contact between the probe stylus and the pad, as the wafer is further moved toward the probe card, the tip end of the probe stylus slides on the pad surface. As the wafer is stopped in position, the slide of the probe stylus on the pad surface also stops.
Generally, the pad has aluminum as its primary component, and aluminum oxide exists on the pad surface. The probe stylus is generally formed of tungsten which is harder than aluminum. Thus, as the probe stylus in contact with the pad slides on the pad surface, the tip end of the probe stylus scribes the aluminum oxide thereon. This causes the tip end of the probe stylus to contact non-oxidized aluminum in the interior, making the probe stylus and the pad electrically conducting with each other at low resistance.
As the tip end of the probe stylus scribes aluminum oxide on the pad surface, pad shavings, such as scribed aluminum, aluminum oxide and others, are attached to the probe stylus. Such pad shavings attached to the tip end of the probe stylus would cause electric resistance upon the inspection and/or measurement of electric properties, thereby adversely affecting the results thereof. Thus, in a mass-production wafer test, probe styluses have been cleaned or polished regularly upon wafer or lot replacement, causing an increase of the wafer test processing time, wearing of the tip ends of the probe styluses due to polishing, breaking of the tip ends during cleaning, and others problems.
The present invention has been made to solve the above-described problems, and its object is to provide a semiconductor device having a pad which eliminates the need for cleaning or polishing a probe stylus.
A semiconductor device having a pad according to the present invention is a semiconductor device having a pad with which a terminal is brought into contact upon inspection or measurement of electric properties of a semiconductor element. First and second conductors are arranged at a surface of the pad. The first conductor has hardness that is greater than that of the second conductor and not less than that of the terminal. The first conductor is arranged at the surface of the pad such that the terminal in contact with and sliding on the pad surface hits against the first conductor at least one time.
According to the semiconductor device having a pad of the present invention, pad shavings attached to the tip end of the terminal are removed as it comes up against the first conductor, making it unnecessary to regularly clean or polish the terminal upon wafer or lot replacement. In addition, the wafer test processing time required for the cleaning or polishing can be saved. Further, wearing of the tip end of the terminal due to polishing as well as breaking of the terminal due to the polishing or cleaning work can be prevented.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.